docs: def getPropAllSubs(self, aURI):
          """
          note: requires SPARQL 1.1
          2015-06-04: currenlty not used, inferred from above
          """
          aURI = aURI
          try:
              qres = self.rdflib_graph.query("""SELECT DISTINCT ?x
                       WHERE {
                           { ?x rdfs:subPropertyOf+ <%s> }
                           FILTER (!isBlank(?x))
                       }
                       """ % (aURI))
          except:
              printDebug(
                  "... warning: the 'getPropAllSubs' query failed (maybe missing SPARQL 1.1 support?)"
              )
              qres = []
          return list(qres)